OVERVIEW
Solfadark is a combination of the solfachord main deck monsters and a dark engine that consists of Armageddon Knight, Zephyros, The PK engine, Destiny Hero Malicious, and the very well known Darkwurm + Dragon Shrine + Gate setup that so many Solfachord decks use. The main idea of the deck is that your gameplay is setup into two separate parts: before pendulum summoning and after pendulum summoning.
The solfachord engine works amazingly to setup for a card like Beyond The Pendulum, which can then search for a missing pendulum scale (usually gate), harmonizer magician as it leads to halq very easily and special summons more material, or Gracia so you can get your field spell out. After your pendulum summon you will mainly be relying on your dark engine pieces (mainly the phantom knight cards unless you draw into Arma) to generate resources because a large majority of the time you will be able to link Beyond The Pendulum and another dark monster such as a plague spreader or darkwurm in order to go into rusty bardiche. From that point you can send cloak, set the brigandine, banish the cloak to add boots, and get creative with the raw amount of materials you can now put on the field. This concept was developed after realizing the deck does not need cards like Loagaeth as they can already get the materials on board for BTP fairly consistently, but struggle to find more resources after pendulum summoning. Cards like Diviner of The Herald are still AMAZING in Solfachord, the only problem is that I am not an oil baron who can drop $240 on a playset of them compared to this much cheaper and equally as effective alternative. Despite being a 45 card deck I have found that its incredibly consistent and also can not think of any cards to take out, if you have any ideas of cards to take out or some ideas on how to improve the deck please shoot me a message on twitter @Gliscare.
Basic Combo:
Assuming a two card hand of Cutia + Dragon Shrine you can go into the following:
Dragon Shrine Send Darkwurm, special darkwurm, add Gate Zero
Normal Cutia, add Dreamia
Darkwurm + Cutia make BTP, set Gate and Dreamia as scales
Add harmonizer to hand
Pendulum Summon Cutia, Darkwurm, and Harmonizer. Activate Harmonizer to special summon Oafdragon
BTP + Darkwurm to make Rusty Bardiche, Bardiche send cloak, set Brigandine and special summon it, banish cloak add Boots and special summon Boots
Harmonizer + Cutia, Boots, or Brigandine to make Halq, special summon plague spreader
Plague Spreader + Oafdragon make Borrelload Savage Dragon, target BTP in grave
From here you can either make a three material Apollousa or use the leftover materials to make IP, then use IP + Halq to make Avramax which can be very hard to out if your opponent is not ready for it.
Banish boots and set fog blade
In addition to that combo theres also a number of extensions you can do via Armageddon Knight by sending cards like Zephyros to the grave so you can summon a hand trap off of halq and then bounce it back to your hand with Zephyros or by sending Malicious to grave for extra material. Whatever you do the deck is shockingly versatile and is an absolute blast to play once you start looking into it more and more. The deck can play through a negate or two depending on the hand, though as it is still solfachords it is painfully fragile at times hence why cards like Instant Fusion and Called By The Grave are here.
"Why is Instant Fusion Here"
Instant Fusion is always an amazing card to draw as it can summon Restrict to protect your Cutia, BTP, or Armageddon Knight from being negated or you can summon Ciel to have a pendulum for BTP in a pinch (it comes up alot more than you'd think). Ciel is an espescially good target as you can pendulum summon her back to the field like any other face up pendulum monster so she can recur herself if you have the proper scales.